/*
 * Copyright (c) 1997, 2007, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */


package com.sun.jmx.snmp.IPAcl;


import java.security.acl.Permission;
import java.util.Vector;
import java.util.Enumeration;
import java.io.Serializable;
import java.net.UnknownHostException;

import java.security.Principal;
import java.security.acl.AclEntry;


/**
 * Represent one entry in the Access Control List (ACL).
 * This ACL entry object contains a permission associated with a particular principal.
 * (A principal represents an entity such as an individual machine or a group).
 *
 * @see java.security.acl.AclEntry
 */

class AclEntryImpl implements AclEntry, Serializable {

  private static final long serialVersionUID = -5047185131260073216L;

  private AclEntryImpl(AclEntryImpl i) throws UnknownHostException {
    setPrincipal(i.getPrincipal());
    permList = new Vector<Permission>();
    commList = new Vector<String>();

    for (Enumeration<String> en = i.communities(); en.hasMoreElements(); ) {
      addCommunity(en.nextElement());
    }

    for (Enumeration<Permission> en = i.permissions(); en.hasMoreElements(); ) {
      addPermission(en.nextElement());
    }
    if (i.isNegative()) {
      setNegativePermissions();
    }
  }

  /**
   * Contructs an empty ACL entry.
   */
  public AclEntryImpl() {
    princ = null;
    permList = new Vector<Permission>();
    commList = new Vector<String>();
  }

  /**
   * Constructs an ACL entry with a specified principal.
   *
   * @param p the principal to be set for this entry.
   */
  public AclEntryImpl(Principal p) throws UnknownHostException {
    princ = p;
    permList = new Vector<Permission>();
    commList = new Vector<String>();
  }

  /**
   * Clones this ACL entry.
   *
   * @return a clone of this ACL entry.
   */
  public Object clone() {
    AclEntryImpl i;
    try {
      i = new AclEntryImpl(this);
    } catch (UnknownHostException e) {
      i = null;
    }
    return (Object) i;
  }

  /**
   * Returns true if this is a negative ACL entry (one denying the associated principal
   * the set of permissions in the entry), false otherwise.
   *
   * @return true if this is a negative ACL entry, false if it's not.
   */
  public boolean isNegative() {
    return neg;
  }

  /**
   * Adds the specified permission to this ACL entry. Note: An entry can
   * have multiple permissions.
   *
   * @param perm the permission to be associated with the principal in this entry
   * @return true if the permission is removed, false if the permission was not part of this entry's
   * permission set.
   */
  public boolean addPermission(java.security.acl.Permission perm) {
    if (permList.contains(perm)) {
      return false;
    }
    permList.addElement(perm);
    return true;
  }

  /**
   * Removes the specified permission from this ACL entry.
   *
   * @param perm the permission to be removed from this entry.
   * @return true if the permission is removed, false if the permission was not part of this entry's
   * permission set.
   */
  public boolean removePermission(java.security.acl.Permission perm) {
    if (!permList.contains(perm)) {
      return false;
    }
    permList.removeElement(perm);
    return true;
  }

  /**
   * Checks if the specified permission is part of the permission set in
   * this entry.
   *
   * @param perm the permission to be checked for.
   * @return true if the permission is part of the permission set in this entry, false otherwise.
   */

  public boolean checkPermission(java.security.acl.Permission perm) {
    return (permList.contains(perm));
  }

  /**
   * Returns an enumeration of the permissions in this ACL entry.
   *
   * @return an enumeration of the permissions in this ACL entry.
   */
  public Enumeration<Permission> permissions() {
    return permList.elements();
  }

  /**
   * Sets this ACL entry to be a negative one. That is, the associated principal
   * (e.g., a user or a group) will be denied the permission set specified in the
   * entry. Note: ACL entries are by default positive. An entry becomes a negative
   * entry only if this setNegativePermissions method is called on it.
   *
   * Not Implemented.
   */
  public void setNegativePermissions() {
    neg = true;
  }

  /**
   * Returns the principal for which permissions are granted or denied by this ACL
   * entry. Returns null if there is no principal set for this entry yet.
   *
   * @return the principal associated with this entry.
   */
  public Principal getPrincipal() {
    return princ;
  }

  /**
   * Specifies the principal for which permissions are granted or denied by
   * this ACL entry. If a principal was already set for this ACL entry,
   * false is returned, otherwise true is returned.
   *
   * @param p the principal to be set for this entry.
   * @return true if the principal is set, false if there was already a principal set for this
   * entry.
   */
  public boolean setPrincipal(Principal p) {
    if (princ != null) {
      return false;
    }
    princ = p;
    return true;
  }

  /**
   * Returns a string representation of the contents of this ACL entry.
   *
   * @return a string representation of the contents.
   */
  public String toString() {
    return "AclEntry:" + princ.toString();
  }

  /**
   * Returns an enumeration of the communities in this ACL entry.
   *
   * @return an enumeration of the communities in this ACL entry.
   */
  public Enumeration<String> communities() {
    return commList.elements();
  }

  /**
   * Adds the specified community to this ACL entry. Note: An entry can
   * have multiple communities.
   *
   * @param comm the community to be associated with the principal in this entry.
   * @return true if the community was added, false if the community was already part of this
   * entry's community set.
   */
  public boolean addCommunity(String comm) {
    if (commList.contains(comm)) {
      return false;
    }
    commList.addElement(comm);
    return true;
  }

  /**
   * Removes the specified community from this ACL entry.
   *
   * @param comm the community  to be removed from this entry.
   * @return true if the community is removed, false if the community was not part of this entry's
   * community set.
   */
  public boolean removeCommunity(String comm) {
    if (!commList.contains(comm)) {
      return false;
    }
    commList.removeElement(comm);
    return true;
  }

  /**
   * Checks if the specified community is part of the community set in this
   * entry.
   *
   * @param comm the community to be checked for.
   * @return true if the community is part of the community set in this entry, false otherwise.
   */
  public boolean checkCommunity(String comm) {
    return (commList.contains(comm));
  }

  private Principal princ = null;
  private boolean neg = false;
  private Vector<Permission> permList = null;
  private Vector<String> commList = null;
}
